What is the difference between CAT-5, CAT-5e, CAT-6, CAT-7?

  • The Simple Answer: 
  • CAT-5 is rated to 100M 
  • CAT-5e is rated to 350M 
  • CAT-6 and CAT6e are rated to 550M or 1000M depending on your source 
  • CAT-7 is supposedly rated to 700M or presumably 1000M

Today there is no approved CAT-6 or CAT-7. While some folks are selling products they call Level 6 or 7, there aren't even specs for them, making CAT-5e the best available option. CAT6 cable is being made with 23 gauge conductor wire as opposed to the slightly smaller 24 gauges for CAT-5e and also has a separator to handle crosstalk better.

Both CAT-5 and CAT-5e have 100-ohm impedance and electrical characteristics supporting transmissions up to 100 MHz. The differences between CAT-5 and CAT-5e show in all aspects of performance: capacitance, frequency, resistance, attenuation, and NEXT. CAT-5e components were designed with high-speed gigabit Ethernet in mind. While CAT-5 components may function to some degree in a gigabit Ethernet, they perform below standard during high-data transfer scenarios. CAT5e cables work with ATM and gigabit speed products. Simply, if you are using a 100Mbps switch, get CAT-5e cable instead of CAT-5.

CAT-5e is formally called ANSI/TIA/EIA 568A-5 or simply Cat-5e (the e stands for 'enhanced'). CAT-5e is completely backward compatible with current CAT-5 equipment. The enhanced electrical performance of CAT-5e ensures that the cable will support applications that require additional bandwidths, such as Gigabit Ethernet or analog video.